Lindsay Lohan has yet to declare which U.S. presidential candidate she will endorse. Perhaps she'll go for Barack Obama. After all, there was that shirtless Hawaiian surf photo of the senator in a People magazine "Beach Babe" spread last year. And he has confessed he did inhale – and snort – as a teenager. Or maybe in her time of substance heaven and hell, the rehab repeater will seek salvation in ordained Baptist minister Mike Huckabee.

Then again, Lohan may not be altogether aware that the presidential primaries are going on.

Celebrity support and endorsements have long been a fun, if somewhat silly, part of the U.S. election process (and scarcely a factor here, since we just don't have that kind of star power, NDPers Sarah Polley and Steven Page of Barenaked Ladies notwithstanding). But this time around, largely because of powerhouse Oprah Winfrey's first-time entry into the presidential election fray, as an Obama supporter, celebrity affiliations appear to be attracting a lot more attention.

There's debate over how much weight the stars carry. Certainly, their financial contributions can't hurt. Dozens of celebrities have helped with fundraising or put their money where their political mindsets are and donated – individuals are allowed to give up to $4,600 (U.S.) per candidate, $2,300 for a primary and $2,300 for a general election, plus up to $28,500 per year to a national party committee. In fact, a number of movie-stars, including Tobey Maguire, Ben Stiller and Paul Newman, have made cash donations to both Clinton and Obama.

BUT THERE'S NO CONSENSUS on whether endorsement from a celebrity will win votes. A study released last September by the Pew Research Center for the People & the Press contends that "political endorsements generally have little impact on voter preference." According to Pew, 69 per cent of Americans say if they heard Winfrey was endorsing a presidential candidate, that would not affect their vote. Of the 30 per cent who said an endorsement would influence them, half indicated it would make them more likely to vote for the candidate while the other half said the opposite.

Still, Pew acknowledged that Winfrey's impact was unpredictable: "There is no telling whether [she] can do for Obama what she has done for the countless books and products she's endorsed over the years."

Indeed, the Pew research preceded the Big O's appearances for Obama in Iowa, New Hampshire and South Carolina, where she helped draw huge crowds to his campaign stops.

Besides Winfrey, the usual cast of liberal stars declared their allegiances some time ago: George Clooney, Matt Damon and Sharon Stone are boffo for Obama; Barbra Streisand and Danny DeVito are ardent Clinton fans.

It's not yet clear how supporters of John Edwards, who dropped out of the race last week, will re-align themselves, but up for grabs are Jackson Browne, Kevin Bacon, Tim Robbins, Bonnie Raitt and John Mellencamp.

The Republican candidates' star power tends to come from the world of business rather than leftish Hollywood. Much hilarity has attended Huckabee's support from born-again Christian and erstwhile film/TV killing machine Chuck Norris. Even so, some say his involvement has boosted the former Arkansas governor's candidacy. Romney's musical "star power," meanwhile, trickles from Donny and Marie, and '50s teen idol Pat Boone.

Fellow Republican John McCain has had to settle for such lesser luminaries as Tom Selleck and Rip Torn, along with Joe Eszterhas, the screenwriter who brought us Basic Instinct and Showgirls.

Now that Rudolph Giuliani has quit the primaries, his star supporters, too, are stranded. They include the hawkish Ron Silver and Dennis Miller, along with Adam Sandler, Kelsey Grammer, Robert Duvall .

And before he dropped out of the race, Democrat Dennis Kucinich had Sean Penn, filmmaker Paul Haggis, Willie Nelson and Hustler publisher Larry Flynt.

Endorsement creates some interesting bedfellows. Indeed, Clinton wins the prize for most sex-obsessed supporters, including Playboy founder Hugh Hefner, tabloid talk-show host Jerry Springer, and adult-movie queen Jenna Jameson, author of How to make Love Like a Porn Star.